Precast concrete structures such as parking garages and bridges rely on concrete steps, pockets or haunches on concrete walls, columns, and beams for support of subsequent concrete beams, Tee's and Double Tee sections spanning between said walls, columns, or beams. These beam-column connections are required to allow for lateral movement due to thermal expansion and contraction. The process of this expansion and contraction movement over time creates a crumbling in the step or haunch which will eventually lead to failure of the entire connection.
The present invention seeks to provide a solution to this problem(s) by a manufactured metal apparatus that incorporates additional support to the column, while simultaneously providing new and additional support to the attaching beam and removing the load from the failing haunch or pocket.
The present invention is constructed of metal plate and extrusions that are engineered per the required loading. The present invention consists of two side plates that mount to the sides or face of the existing column which are parallel to the beam via embedded anchors, a back plate when required, a front load shelf and an adjustable bearing plate.
Preferably, the adjustable load-bearing plate will carry a low friction bearing pad or a linear roller bearing assembly to enable free movement, whether it be expansion, contraction or seismic. Many types of low friction devices can be incorporated here.
Preferably, with the device fully attached around all four sides or face of the column or anchored into the surrounding solid structure, the additional metal material acts as a brace to the column or other support structure and provides a method of applying a load, via a load cell, hydraulic jack or other similar load-applying device mounted between the front load shelf and the adjustable load bearing plate, to the beam straight from the column. In a precast structure, such as a parking garage, by not applying a load to the precast floor system, there is a tremendous economic gain in time and utilization of the parking area. Once the load is applied to the beam, the load is removed from the failing step or haunch. The bearing plate adjustments are tightened in place and the load-applying device can be removed. The load has then been conveyed fully or partially to the bearing plate of the device.
Additionally, if so desired, during apparatus design, the location of the bearing plate can allow for placement of a load-applying device behind it to remove the load from the bearing plate and provide maintenance to, or change out, the low friction device.